Pg. 68-71 Technological advances in the litchi cultivar development programme

South Africa has a long history of litchi cultivation as well as litchi research, with a litchi breeding programme that commenced in 1992. Through the years, a number of new litchi cultivars were introduced to the industry. Although the new introductions were welcomed, they did not always perform as expected, and there were still areas in the production cycle that needed attention. It was realised that all initial efforts in litchi plant improvement were hampered by a lack of genetic diversity available in the South African germplasm collection, and that old methodologies of open-breeding systems were not advancing quickly enough. Subsequently a quest for high quality cultivars worldwide lead to the importation of new germplasm with 30 new litchi cultivars and four longan cultivars imported from Australia and Israel since 2013. The addition of these new cultivars to the breeding programme have substantially increased the probability of producing new and improved genotypes in years to come. Optimising the breeding techniques included parent characterisation, the establishment of a genotype reference database for litchis using molecular marker technology, and pollination studies aimed at viability and cross compatibility.

Summary:

• South Africa’s litchi breeding program started in 1992, aiming to improve cultivars, but progress was initially limited by low genetic diversity in local germplasm and slow open-breeding systems.
• Since 2013, 30 new litchi cultivars and 4 longan cultivars were imported from Australia and Israel, significantly expanding the gene pool and increasing chances for improved genotypes.
• Molecular marker technology, particularly Sequence-related amplified polymorphism (SRAP) markers, has been introduced for genetic characterization to complement phenotypic evaluation, helping to identify redundant or misidentified cultivars and select genetically diverse parents for breeding.
• Litchi breeding has evolved from open pollination to controlled hand pollination with specific parent crosses to combine desired traits more effectively; over 7,000 seedlings are under evaluation.
• Promising new selections have been identified and are undergoing further propagation and commercial assessment; one recently released cultivar is R1G22 Early Delight, with more selections planned for commercial trials.
• The use of biotechnology along with conventional breeding allows linkage of molecular markers to traits, aids identification of genetic diversity gaps, and enhances targeted parent selection.
• The program has established Phase 1 and Phase 2 blocks under observation and evaluation and aims to expand cooperative trials to different climatic regions to confirm cultivar performance before commercial release.
• The latest Plant Breeders Right application involves the Friedenheim selection, a mid-season cultivar with favorable fruit size and quality traits.
• Financial support comes from the South African Litchi Growers Association, Agricultural Research Council, and National Research Foundation.